Package org.evrete.api

Interface ExpressionResolver

public interface ExpressionResolver

An interface with a set of basic methods that are necessary for parsing string expressions.

Method Summary

Modifier and Type	Method	Description
default Evaluator	buildExpression(String expression, NamedType.Resolver resolver)	Deprecated. use buildExpression(LiteralExpression) instead
default LiteralEvaluator	buildExpression(LiteralExpression expression)	This method parses a string argument and returns an Evaluator if possible.
Collection<LiteralEvaluator>	buildExpressions(Collection<LiteralExpression> expressions)	This method builds literal expressions all at once and returns a collection of compiled results.
FieldReference	resolve(String arg, NamedType.Resolver resolver)	This method takes a string as an argument and builds a FieldReference if possible.
default FieldReference[]	resolve(NamedType.Resolver resolver, String... strings)

Method Details

resolve

FieldReference resolve(String arg,
 NamedType.Resolver resolver)

This method takes a string as an argument and builds a FieldReference if possible.

For example, if the argument is "$c.category.id", the implementation might do the following:

1. Use the supplied resolver to identify which NamedType this expression refers to (let's say it's a Customer fact, named "$c")
2. Use the resolved NamedType to parse the remaining part of the argument, "category.id", by the means provided by the Type interface.

Parameters:

arg - a String to parse

resolver - a mapping function between fact name and full NamedType

Returns:

returns FieldReference instance or throws an IllegalArgumentException

Throws:

IllegalArgumentException - if the argument can not be resolved

resolve

default FieldReference[] resolve(NamedType.Resolver resolver,
 String... strings)

buildExpression

@Deprecated
default Evaluator buildExpression(String expression,
 NamedType.Resolver resolver)
                           throws org.evrete.runtime.compiler.CompilationException

Deprecated.

use buildExpression(LiteralExpression) instead

Throws:

org.evrete.runtime.compiler.CompilationException

buildExpression

default LiteralEvaluator buildExpression(LiteralExpression expression)
                                  throws org.evrete.runtime.compiler.CompilationException

This method parses a string argument and returns an Evaluator if possible.

Parameters:

expression - - literal expression and its context

Returns:

returns an Evaluator instance or throws an exception

Throws:

org.evrete.runtime.compiler.CompilationException - if the argument can not be compiled

IllegalArgumentException - if the expression can not be resolved

IllegalStateException - if the resolver is not in an appropriate state

buildExpressions

Collection<LiteralEvaluator> buildExpressions(Collection<LiteralExpression> expressions)
                                       throws org.evrete.runtime.compiler.CompilationException

This method builds literal expressions all at once and returns a collection of compiled results. Order is not guaranteed, use the LiteralEvaluator.getSource() method to associate the resulting evaluators with the method's argument list.

Parameters:

expressions - - literal expressions

Returns:

collection of LiteralEvaluator instances

Throws:

org.evrete.runtime.compiler.CompilationException - if the argument can not be compiled

IllegalArgumentException - if the expression can not be resolved